Medicaid math—fun and confusion with numbers

Medicaid math—fun and confusion with numbers

October 28, 2011

Pity the poor policymaker trying to make budget decisions based on expert analysis.

New projections for Medicaid growth under the Patient Protection and Affordable Care Act could be as low as 8.5 million people or as high as 22.4 million new enrollees. That assessment is fluid and differs from other recent projections.

Insurance expansion under the Affordable Care Act promises to provide coverage for patients who previously could not pay medical bills or avoided care for lack of insurance. Hospitals and medical groups that anticipate the law will deliver more insured patients. Varying projections raise some doubt as to how far coverage by Medicaid will actually reach.

On that point, the Harvard School of Public Health researchers who drafted the new Medicaid projections differ with two previously published federal estimates.

The Congressional Budget Office estimated Medicaid would grow by 16 million people in 2019 under the law, which increases eligibility for the safety-net insurer and provides significant federal financing for the expansion.

The CMS came in slightly higher with a projected increase of 18 million enrollees in 2019.

The Harvard researchers, Benjamin Sommers, Arnold Epstein and Katherine Swartz, put their best estimate at 13.4 million new enrollees in 2019.

The CBO relied on different data and that largely accounted for the disparity between estimates by the federal economists and the researchers. Meanwhile, CMS based the projection on an ambitious assumption that 97% of eligible Medicaid enrollees would seek coverage, compared with the 62% for the Harvard estimate.

If estimates published in Health Affairs are accurate, federal Medicaid spending will grow by $58 billion—though that could be as little as $34 billion or closer to $98 billion. Another 7,400 doctors would be needed (4,500 at the low end, 12,100 at the high end).

And another 5,300 doctors (or anywhere from 2,200 to 12,500 doctors) who previously cared for privately insured patients would now treat Medicaid patients.